No display on handset after teardown?

I bought a cheap 3g for a friend of mine. Battered, beaten, and with a shattered screen.

I ordered a new LCD, digitizer and casing for the phone. As the LCD and digitizer arrived first I fitted those last week. No problem, the phone worked great, aside form the very tatty rear housing.

The part arrived today. Stripped the phone and reassembled it in the new housing. Worked fine agin, except the dock connector was at a slight angle in the new housing. Stripped it down to reposition it slightly, reassembled it and..... nothing.

The phone is recognized in itunes, and then on the vibrate on off button works, so I know the phone is working, just not kicking out any display. I tried the old LCD in it. Although cracked it would have at least lit up but nothing is being displayed though that, so I can only assume its an issue with the logic board outputting a display.

Does anyone have a solution or remedy or any suggestions to what I should try?

Thank you.